Conversions between mass and moles are very important in chemistry. They help us connect what we can see (like the amount of a substance) with the tiny particles we can't see (like atoms and molecules).

Here’s why these conversions are important:

1. Accurate Calculations: They help chemists know how much of each substance is needed in a chemical reaction.

2. Example: Let’s say you have 18 grams of water (H₂O). To find out how many moles that is, we use something called molar mass, which is 18 grams for one mole of water.

   So, to find the moles of water, you would do the following:

   $\text{Moles of } H_{2}O = \frac{18 \text{ g}}{18 \text{ g/mol}} = 1 \text{ mol}$

3. Understanding Relationships: When we convert between mass and moles, it helps us see how different substances mix together or change during reactions.

Knowing how to do these conversions is really important for getting chemical reactions just right!